1. Field of the Invention
The present invention relates to devices for converting contaminated or impure water into potable or pure drinking water, and more particularly to a portable water filtering and purifying device having a plurality of separate chambers wherein the water is initially isolated in a first chamber and immersed in a disinfecting agent, and then is transferred to another chamber for further filtering and/or purifying, and more particularly still to a portable water filtering and purifying device that is customizable with particular treating agents to simply and easily remove specific contaminants from a water supply.
2. Description of Related Art
Contaminated drinking water is a leading cause of health problems and concerns throughout the world. While such problems and concerns are encountered by millions on a daily basis, particularly in less developed countries, ensuring the safety of a supply of water is also an important concern for soldiers, hikers, international travelers and others. Various waterborne diseases are commonly found in untreated water, caused by microbial agents including protozoan parasites that cause Giardiasis and Cyclosporasis, and Crytosporidium parvum, viruses such as the hepatitis A and other viruses, and bacteria such as E. coli, salmonella typhi which causes Typhoid fever, Vibrio cholerae, and shigella species. Symptons include fever and diarrhea, rashes, cramps, jaundice, liver disease as well as other diseases, and while in many cases such ailments can be treated if attended to quickly, if not treated can worsen and cause permanent serious conditions and often death, particularly in the young and elderly, as well as those having compromised immune systems.
In addition to concerns related to untreated water, treated water supplies may also contain contaminants. While in developed countries most cities and large towns have large piped water systems for continually transporting relatively high quality treated water to users, such tap water is only safe to drink if it has been fully treated and disinfected, and if the water system is well operated and maintained. Bottled-water is also becoming increasingly popular, and although usually presumed to be safe by most users, may also be contaminated not only by microbial hazards such as those already mentioned above but also by any number of chemical and physical hazards. Possible chemical hazards include heavy metal ions, lead, arsenic and benzene, while physical hazards include glass chips and metal fragments.
A variety of portable devices for filtering and purifying water from untreated sources such as lakes and streams, improperly maintained piped water supplies, and other sources, to make such water potable are found in the prior art. For example, numerous portable straw-type devices wherein the user places his or her mouth over one end of an elongated casing and sucks inwardly in the same manner as with a conventional drinking straw, causing the water to pass across or through a filter in the device, are known. Also known are gravity-activated filter assemblies having at least two compartments through which water is passed to remove various particulates, organisms, and ions. A significant disadvantage of mouth suction and gravity activated filtering and purifying devices, however, is that there is a practical limit to the pore size of the openings in the filter elements used, measured in microns, which pore size determines what size particles are prevented from passing through the filter. While filters having as small pore sizes as possible are obviously more desirable, since more microbial and other contaminants will thereby be filtered from the water, if the pore size of the filter is made too small, it becomes impossible for the user to pass a meaningful amount of water through the filter and straw merely by mouth suction or gravity pressure. For example, while a maximum pore size of 4.0 microns will filter out Giardia cysts, a maximum pore size of 0.2 microns is required to filter out bacteria, which generally have a size of between 0.2 and 10 microns. Viruses, which typically range in size from 0.0004 to 0.1 microns, are too small to be filtered out by most filters, but many viruses will attach themselves to a larger host bacteria, and these viruses can be removed by removing the host bacteria. Even where a pre-filter is used to filter out larger particles that would immediately clog the main filter, the smaller the pore size of the main filter, the more quickly it will become clogged and ineffective. Several pressurized filtering and purifying devices are known, but they are bulky and inconvenient to carry and use and thus are not truly portable.
The use of granulated activated carbon (GAC) as a water filtration media is well known, since activated carbon is efficient in removing or filtering out small contaminants from water. However, bacteria and viruses in the water can grow in the carbon bed, and activated carbon as a filter means does not work well with heavy metals, as well as certain chemicals such as alcohols, glycols, strong acids and bases. Thus, other agents for destroying certain viruses and bacteria, as well as for eliminating heavy metals and other contaminants are also known.
A further problem with water filters having small pore sizes is that they quickly become clogged with contaminants and materials that have been removed from the water. As a result, many such filters must be replaced continually with a new, clean filter, since even if, for example, the filter is sterilized by dipping it in a disinfecting solution such as bleach to kill harmful parasites and the like in the filter, such contaminants although possibly no longer harmful if ingested, nevertheless remain trapped in and clogging the filter cartridge. Thus, the cost of such filters is problem, particularly in less wealthy countries wherein while persons having a filtering device can avail themselves to a supply of clean and potable water as long as the device contains a new filter, once the filter become clogged either the user must have a replacement filter available, which is expensive, impractical, and unlikely, or the device will be rendered useless. The present inventor, recognizing the problems associated with existing portable water filtering and purifying devices, has now developed an improved water filtering and purifying device that can be carried easily in a backpack, bag, or clothing pocket and that can be used with filters having pore sizes small enough to filter out some viruses, down to 1 micron, thus removing virtually all contaminants from the water. In such device the present inventor has also provided an arrangement for clearing contaminants and materials from the filter device quickly and easily, thereby making the filter reusable and extending its life more or less indefinitely. Such improvements are provided by the present device which not only can pump or force water through filters having smaller pore sizes than would be possible with only manual suction, but in addition said same pumping action can be used to force contaminants and other materials clogging the filter out of such filter so that the device is ready to be reused.